With the rapid development of flat-panel display technology, a display product whose picture is clear, colorful and vivid has drawn increasing attention and expectation from the public.
In order to provide these enhanced properties, improved binder compositions are desired. Regarding photosensitive binder compositions obtained by mixing a green pigment powder with a binder composition and the green photoresist prepared from the photosensitive binder composition, the binder compositions conventionally used are mostly composed of an alkali soluble binder, photopolymerizable monomer(s) containing a dipentaerythritol group, a photoinitiator, a levelling agent and a solvent; the conventional green pigment powder is usually G36; when they are mixed together, the G36 pigment powder can be dispersed into the photosensitive binder composition system relatively well but the green photoresist prepared thereby is barely satisfactory in terms of contrast and colour gamut. Therefore, in order to improve the effect of green photoresist in terms of contrast and colour gamut, competitive photoresist manufacturers use superior green pigment powder to produce photoresist having higher contrast. With smaller particle size and greater brightness, G58 green pigment powder stands out from high-performance green photoresists.
However, G58 green pigment is a pigment powder which cannot be easily refined. After being dispersed stably, it usually cannot be easily matched with the existing photosensitive binder composition formulation system and can easily cause problems such as poor heat resistance, poor development properties, rough pixel surface, and marginal residue. Alkali soluble binder is one of the most important components of the photosensitive binder composition in the original photosensitive binder composition formulation and plays a relatively essential role in solving problems of the composition such as poor heat resistance. Therefore, there is still a need for a new alkali soluble binder for producing a photosensitive binder composition having excellent properties such that G58 green pigment is better dispersed in the binder system.
It has surprisingly been found that if functional polymerization monomer(s) are added into the alkali soluble binder, the functional polymerization monomer(s) can not only introduce alkyl and anhydride into the alkali soluble binder so as to adjust its polymerization degree and viscosity but also resolve problems of the binder such as poor heat resistance, rough pixel surface, marginal residue. It can also be subjected to a neutralization reaction with alkali solvent during the course of alkali development so as to improve the development effect of alkali soluble binder, such that G58 green pigment having a smaller particle size is better dispersed in the alkali soluble binder and a photosensitive binder composition having enhanced properties is further formed.